Method of forming a delamination-resistant three dimensional double curvature surface colored composite article

ABSTRACT

In this method, a delamination resistant three dimensional double curvature surface colored composite article is made by providing a membrane with a delamination-resistant coloring coating and applying the membrane to an injection mold having mold halves, a mold parting face, mold cavity edge and a mold cavity therein for the formation of an injection molded article, and injecting molten plastic into the mold cavity in order to form a three dimensional double curvature surface composite article with the membrane bonded to the injected plastic. Alternatively, the membrane is thermoformed.

This application is a continuation of application Ser. No. 10/329,170which is scheduled to issue as U.S. Pat. No. 6,916,439 on Jul. 12, 2005,which, in turn, is a continuation of application Ser. No. 09/677,713which issued as U.S. Pat. No. 6,497,833 on Dec. 24, 2002, which claimspriority of Provisional Patent Application No. 60/156,723 filed on Sep.30, 1999 which is incorporated herein by reference. Further, applicationSer. No. 09/677,713 incorporates by reference U.S. Pat. No. 5,401,457.Accordingly, the specification section of this continuation applicationhas been amended, without adding any new matter, by inserting lines 17to 22 in page 7 of this application. This amendment of the specificationhas basis in Column 2, lines 1 to 8 in U.S. Pat. No. 5,401,457.

FIELD OF THE INVENTION

The present invention is in the field of colored laminated thermoplasticand thermoset sheet materials. In particular it addresses a method forenhancing the resistance to delamination of such sheet materials

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a side view of an apparatus for making a two-thermoset-layersdelamination resistant colored membrane.

FIG. 2 is a side view of an apparatus for making a two-thermoplasticlayers delamination resistant colored membrane.

FIG. 3 is a side view of an apparatus for making a thermoset bottomlayer and a thermoplastic top layer delamination resistant coloredmembrane.

FIG. 4 is a side view of an apparatus for making a thermoplastic bottomlayer and a thermoset top layer delamination resistant colored membrane.

FIG. 5 is a cross-sectional view of uncured/unsolidified membrane afterlaying fibrous web on its surface.

FIG. 6 is a cross-sectional view of a two-layer delamination-resistantcolored membrane.

FIG. 7 is a cross-sectional view of a three-layer delamination-resistantcolored membrane.

DETAILED DESCRIPTION OF THE INVENTION

FIG. (1) shows an apparatus 52 for making a two-thermoset-layerdelamination-resistant colored membrane composite. As shown therein, anuncured thermoset membrane 14 is extruded, in a sheet form, frommembrane-forming die 15. The membrane is formed by mixing of its firstreactive component 1, contained in tank 45, with its second reactivecomponent 2, contained in tank 46. For coloring, reinforcement, cellularstructure (foam) development or for other purposes, liquid additives 4,contained in tank 47, and/or solid additives 3 may be added to thethermoset membrane-forming mixture, in tank 48. Typically, mixture 6 ishomogenized, for example by mixing stirrer 5 or other means. Aftermixing all the components of membrane 14, the mixture is allowed to flowinto membrane-forming die 15 by opening valve 7. In some applications apump may also be used in order to generate the required pressure anddesired volume flow rate. As uncured thermoset membrane 14 is extrudedfrom die 15, it is laid on a non-stick release liner 8 which is unwoundfrom a roll of non-stick release liner 33, on conveyor belt 30, andrewound into a roll 35 which is driven by friction drive roll 34. Guiderolls 39, 42 and 36 are used to direct the release liner 8 and coloredlaminated composite as the process is performed from one end ofapparatus 52 to its other end. Alternatively, release liner 8 may beeliminated if conveyor belt 30 is made of a non-sticking material or iscoated with a non-sticking release coating. Conveyor rolls 31 and 32provide an adjustable or constant rate of travel to belt 30, which, incombination with the rate of flow of mixture 6, determine the thicknessof membrane 14. The thickness of membrane 14 is an important parameterin this process since subsequent operations, for example thermoformingor injection molding a layer of molten plastic on it and subsequent orsimultaneous stretching of the composite may result in significantsurface deformation which may alter the exterior color or the surfacecharacteristics of the delamination-resistant colored membrane. Anexample of such subsequent operations that may be performed on thecolored laminated composite of the present invention is disclosed inU.S. Pat. No. 5,401,457 which is incorporated herein by reference.

As uncured thermoset membrane 14 is extruded on release liner 8, its topsurface 9 is of a tacky nature. Depending on its rate of curing orsolidification, its surface tack and viscosity, a first partial curingzone 16 is provided in order to allow for adequate development ofsurface of membrane 14 before entering the fibrous media applicationzone 18. In doing so, one can have at least a portion of fibers, infibrous web 37 or sprinkled fibers 38, partially encapsulated withinmembrane 14, as shown in FIG. 5. Such partially encapsulated fibers,when also subsequently partially encapsulated within coloring coating20, serve as an interfacial reinforcement that provides a bond betweenthe two layers of colored composite 44. Such an interfacialreinforcement profoundly enhances the resistance to delamination betweenthe layers of the colored composite.

Fibrous web 37 is fed into zone 18 from fibrous web roll 10. In someapplications, a guide roll 41 is used to direct fibrous web 37 to thedesired location, height and point of contact with uncured orunsolidified surface 9 of membrane 14.

Fibrous web 37 may be made of woven, knitted , stitch-bonded ornon-woven fibers and/or yarns. In its most preferred embodiment, fibrousweb 37 is made of a needle punched non-woven in order to provide themost possible tensile and in-plane shear deformability, withoutbreakage, during subsequent thermoforming or injection molding processeswhere the colored composite may be formed into three dimensional doublecurvature surfaces. The fibers of fibrous web 37 may be of a naturalorigin (for example cotton or other natural staple fibers) or of aman-made type, such as synthetic fibers, regenerated fibers or metallicfibers.

Alternatively or in addition to fibrous web 37, loose fibers 12,contained in hopper 11, may be sprinkled on the top surface 9 ofuncured/unsolidified membrane 14 by using fiber sprinkler 13. As shownin FIG. (1), sprinkled fibers 38 are deposited on membrane 14 in fibrousmedia application zone 18. Similar to fibrous web 37, sprinkled fibers38 may be of a natural origin or of a man-made type, such as syntheticfibers, regenerated fibers or metallic fibers.

In a similar manner, an uncured thermoset coloring coating 20 is formedand extruded through coloring coating application die 50 onto thesurface of membrane 14 covered by fibrous web 37 and/or sprinkled fibers38.

Coloring coating 50 is also prepared in a manner similar to that ofpreparing membrane 14. A first reactive component 22 and a secondreactive component 23, of coloring coating 20, are directed from tanks28 and 29 into mixing tank 51. Liquid additives 24, which may alsoinclude coloring agents or pigments, are also directed from tank 49 intomixing tank 51. Similarly, solid additives 25 may be added to thecoloring coating mixture 26 in tank 51. The mixture is then homogenizedby rotating stirrer 27 or some other means and is allowed to flow intocoloring coating application die 50 by opening valve 17 and controllingflow rate to yield the desired thickness of coloring coating 20. Asdiscussed above and for the same reasons stated in connection withmembrane 14, the thickness of coloring coating 20 is an importantparameter and a variety of means, known in the art, including meteringpumps may be used for its control.

As uncured coloring coating 20 is extruded onto the surface of membrane14, which is covered by fibrous web 37 and/or sprinkled fibers 38, itsbottom surface 21 is of a tacky or liquid nature and thus encapsulatesthe remaining portions of those fibers which had been partiallyencapsulated within membrane 14. The two-layer thermoset composite thenproceeds through curing or cooling zone 19 where the components arefully cured/solidified and directed to a take up unit along thedirection of arrow 43 as a delamination-resistant colored composite 44.

Using same or similar components and zones (as 8, 10, 11, 12, 13, 16,18, 19, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 41, 42, and 43) shown inFIG. (1) and described above and following similar steps and thicknesscontrols, an apparatus 63 for making a thermoplasticdelamination-resistant colored composite 68 is shown in FIG. (2). Asshown therein, a first molten thermoplastic membrane 53 is extruded,through molten membrane extrusion die 57, in a similar manner and istreated in the same way as uncured thermoset membrane 14. Hopper 61feeds the thermoplastic material into plasticating extruder 59 which, inturn, melts it and feeds it into die 57. Also, similarly, the topsurface 55 of molten thermoplastic membrane 53 is treated and coatedwith fibrous web 37 and/or sprinkled fibers 38 in a manner similar tothat of treating top surface 9 of membrane 14. Also, as shown in FIG.(2), a similar thermoplastic coloring coating 54 is produced by usingfeeding hopper 62, plasticating extruder 60 and molten coloring coatingextrusion die 58. The thermoplastic material contained in feeding hopper62 may be of a pre-compounded colored nature or a blend of colored anduncolored thermoplastic materials selected to produce the desiredexterior color of composite.

Also, similarly, the bottom surface 56 of molten thermoplastic coloringcoating 54 is treated and coated with fibrous web 37 and/or sprinkledfibers 38 in a manner similar to that of treating top surface 9 ofmembrane 14.

Again, using combinations of same or similar components and zones, asshown in FIGS. (1) and (2) and as described above, FIG. (3) shows a sideview of an apparatus 64 for making a thermoset bottom layer and athermoplastic top layer delamination resistant colored composite 66 andFIG. (4) shows a side view of an apparatus 65 for making a thermoplasticbottom layer and a thermoset top layer delamination resistant coloredcomposite 67.

FIG. 5 shows an uncured or molten membrane 69 in fibrous applicationzone 18 with fibers 73 completely encapsulated within it, fibers 71partially encapsulated in it and other loose fibers 72 lying completelyoutside of it. As shown therein, first layer 70 has a bottom surface 95and a top uncured or molten surface 85.

FIG. 6 shows a cross-sectional view of a two-layerdelamination-resistant colored composite 74 comprising bottom layer 70,top layer 84, joined at their interface 86, and having fibers 71partially encapsulated in bottom layer 70 and partially encapsulated intop layer 84, thus providing enhanced resistance to delamination.

FIG. 7 shows a cross-sectional view of a three-layer delaminationresistant colored composite 75 comprising bottom layer 76, middle layer77, top layer 78, joined at their respective interfaces 87 and 88 and,as described earlier, having an enhanced resistance to delaminationwhich is attributable to interlaminar reinforcement fibers 80 and 82.Such a colored composite may be produced by combining a plurality ofsuccessive membrane-making steps, fibrous web/sprinkled fibersapplication zones and coloring coating membrane application zones ofthermoplastic and thermoset materials as described in this invention.

In the present invention, a process for forming a color coated ordecorated article is provided by applying a color coated material to aninjection mold having mold halves, a mold parting face, mold cavity edgeand a mold cavity therein for the formation of an injection moldedarticle, and injecting molten plastic into said mold cavity to form alaminated article with the color coated material bonded to the injectedplastic.

It should be noted that other variants of the above described methods orcombinations of their steps may be utilized, for coloring the surface ofa thermoset or thermoplastic membrane, without departing from the spiritand scope of the disclosed invention.

1. A method of forming a delamination resistant three dimensional doublecurvature surface colored composite article, comprising the steps of: 1)providing a membrane with a delamination-resistant coloring coating,prepared by; a) forming a membrane, said membrane having a tackysurface, b) laying a fibrous material onto said tacky surface of saidmembrane such that portions of fibers, comprising said fibrous material,are encapsulated, below said surface of said membrane and within saidmembrane, and c) applying an uncured thermoset coloring coating, saidcoloring coating having a bottom surface, said bottom surface being of atacky nature, onto said fibrous material such that remaining portions ofsaid fibers are encapsulated within said coating, whereby fibersencapsulated by and originating within said membrane are also partiallyencapsulated and terminating within said coloring coating, thusproviding a delamination-resistant mechanical bond between said membraneand said coloring coating, and 2) applying said membrane with adelamination-resistant coloring coating to an injection mold having moldhalves, a mold parting face, mold cavity edge and a mold cavity thereinfor the formation of an injection molded article, and 3) injectingmolten plastic into said mold cavity to form a three dimensional doublecurvature surface composite article with said membrane bonded to theinjected plastic.
 2. A method of forming a delamination resistant threedimensional double 2 curvature surface colored composite article,comprising the steps of: 1) providing a membrane with adelamination-resistant coloring coating, prepared by; a) forming amembrane, said membrane having a tacky surface, b) laying a fibrousmaterial onto said tacky surface of said membrane such that portions offibers, comprising said fibrous material, are encapsulated, below saidsurface of said membrane and within said membrane, and c) applying anuncured thermoset coloring coating, said coloring coating having abottom surface, said bottom surface being of a tacky nature, onto saidfibrous material such that remaining portions of said fibers areencapsulated within said coating, whereby fibers encapsulated by andoriginating within said membrane are also partially encapsulated andterminating within said coloring coating, thus providing adelamination-resistant mechanical bond between said membrane and saidcoloring coating, and 2) subsequently, thermoforming said membrane witha delamination-resistant coloring coating into a three dimensionaldouble curvature surface composite article.
 3. A method of forming adelamination resistant three dimensional double curvature surfacecolored composite article, comprising the steps of: 1) providing amembrane with a delamination-resistant coloring coating, prepared by; a)forming a membrane, said membrane having a tacky surface, b) laying afibrous material onto said tacky surface of said membrane such thatportions of fibers, comprising said fibrous material, are encapsulated,below said surface of said membrane and within said membrane, and c)applying a thermoplastic coloring coating, said coloring coating havinga bottom surface, said bottom surface being of a tacky nature, onto saidfibrous material such that remaining portions of said fibers areencapsulated within said coating, whereby fibers encapsulated by andoriginating within said membrane are also partially encapsulated andterminating within said coloring coating, thus providing adelamination-resistant mechanical bond between said membrane and saidcoloring coating, and 2) applying said membrane with adelamination-resistant coloring coating to an injection mold having moldhalves, a mold parting face, mold cavity edge and a mold cavity thereinfor the formation of an injection molded article, and 3) injectingmolten plastic into said mold cavity to form a three dimensional doublecurvature surface composite article with said membrane bonded to theinjected plastic.
 4. A method of forming a delamination resistant threedimensional double curvature surface colored composite article,comprising the steps of: 1) providing a membrane with adelamination-resistant coloring coating, prepared by; a) forming amembrane, said membrane having a tacky surface, b) laying a fibrousmaterial onto said tacky surface of said membrane such that portions offibers, comprising said fibrous material, are encapsulated, below saidsurface of said membrane and within said membrane, and c) applying athermoplastic coloring coating, said coloring coating having a bottomsurface, said bottom surface being of a tacky nature, onto said fibrousmaterial such that remaining portions of said fibers are encapsulatedwithin said coating, whereby fibers encapsulated by and originatingwithin said membrane are also partially encapsulated and terminatingwithin said coloring coating, thus providing a delamination-resistantmechanical bond between said membrane and said coloring coating, and 2)subsequently, thermoforming said membrane with a delamination-resistantcoloring coating into a three dimensional double curvature surfacecomposite article.